With the 3DS I can do a system transfer, but I need both DS' for that to work. Which means I can't sell my current, soon-to-be obsolete 3DS without losing everything I bought online. Sure, I can transfer it, assuming I keep this 3DS, but I can't recoup some of my spent money until after the transfer.
...So, it's a big deal that you can't sell your old system before you buy a new one? No, I do not see this as being a great concern to anyone.
If you're suggesting you would be able to sell your current 3DS on the secondhand market for a substantially greater sum at the moment than you will when the new model comes out, that also seems unlikely. The new 3DS will be available at the price of the current 3DS.
The other side are apologists which seem more interested in justifying the move than actually explaining how it isn't a bad move.
We are not privy to the internal workings of Nintendo, ergo, how should we be able to explain their reasoning? To assume malice or ignorance seems like an unreasonable leap.